[html4all] [html4all.org] Content-type negotiation as an alternative to ALT, LONGDESC and fallback

[Philip TAYLOR]

Jason White wrote:
> On Sat, Aug 25, 2007 at 08:20:34AM -0500, Robert Burns wrote:
>> I have to say that is an intriguing idea. I had never though of  
>> delivering text instead of an image through negotiation. I'll have to  
>> think about it further, but it might be a workable solution in some  
>> settings. I wouldn't want us to just give up on providing an HTML  
>> solution to the problem, but until that solution exists, this could  
>> work.
> 
> The main problem is that HTML (and XHTML) documents are not always served via
> HTTP. If they are on my local file system, or a networked file system such as
> NFS or AFS, there won't be any HTTP negotiation.

Agreed (though I frequently wonder whether this separation
of protocol from content is sub-optimal in this case)

> Finally, not all authors are able to configure their servers, as in certain
> hosted situations.

That /should/ not matter, provided that the servers are
correctly configured in the first place; it is the
browser that needs to be configured to emit the correct
"Accept:" header for this to work.  Perhaps more
important is that, as far as I know, IIS (even at IIS 6)
doesn't support content negotation at all, which does
rather render the whole idea a non-starter.  Sad, really :
Microsoft abuse <Object> and don't support content
negotation : I'm far from a Microsoft hater (apart from Word !),
but I do wish they'd get their act together.
> 
> Thus, while it may work in some cases, it isn't a substitute for a solution
> implemented entirely in markup; and I wouldn't mention it on the main list, as
> it could then lead to a debate about the circumstances in which it is
> inadequate, distracting attention from the problem of deciding what
> markup-based solution the spec should provide.

OK, advice heeded :-)
** Phil.